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Joint spatial‐spectral reconstruction and k‐t spirals for accelerated 2D spatial/1D spectral imaging of 13 C dynamics
Author(s) -
Gordon Jeremy W.,
Niles David J.,
Fain Sean B.,
Johnson Kevin M.
Publication year - 2014
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24796
Subject(s) - oversampling , imaging phantom , image resolution , physics , nuclear magnetic resonance , temporal resolution , computer science , spiral (railway) , iterative reconstruction , spectral imaging , algorithm , optics , artificial intelligence , mathematics , bandwidth (computing) , computer network , mathematical analysis
Purpose To develop a novel imaging technique to reduce the number of excitations and required scan time for hyperpolarized 13 C imaging. Methods A least‐squares based optimization and reconstruction is developed to simultaneously solve for both spatial and spectral encoding. By jointly solving both domains, spectral imaging can potentially be performed with a spatially oversampled single echo spiral acquisition. Digital simulations, phantom experiments, and initial in vivo hyperpolarized [1‐ 13 C]pyruvate experiments were performed to assess the performance of the algorithm as compared to a multi‐echo approach. Results Simulations and phantom data indicate that accurate single echo imaging is possible when coupled with oversampling factors greater than six (corresponding to a worst case of pyruvate to metabolite ratio < 9%), even in situations of substantialT 2 *decay and B 0 heterogeneity. With lower oversampling rates, two echoes are required for similar accuracy. These results were confirmed with in vivo data experiments, showing accurate single echo spectral imaging with an oversampling factor of 7 and two echo imaging with an oversampling factor of 4. Conclusion The proposed k‐t approach increases data acquisition efficiency by reducing the number of echoes required to generate spectroscopic images, thereby allowing accelerated acquisition speed, preserved polarization, and/or improved temporal or spatial resolution. Magn Reson Med 71:1435–1445, 2014. © 2013 Wiley Periodicals, Inc .